ZR-1 Net Registry Forums - View Single Post

XfireZ51 · 01-30-2013

Scott,

I wrote this on another board dealing w the issue of re-mapping the MAT table when it has been relocated and used as an IAT instead.

I appreciate that you keep bringing this topic up because it does interest me particularly since I moved by MAT sensor from the airhorn to a spot behind the air filter but ahead of the airbridge(which BTW needs to be stiffened or it will collapse at WOT). Now the table in the $D0A mask is a
MAT Temp C v Compensation. The temps in the table go to 151 C which makes sense since the airhorn is attached to the motor. However, by moving the MAT to an IAT location, my thinking is the IAT will never "see" that 151 C temp since incoming air probably won't go above say 51-55C. And at speed, the IAT should be measuring close to ambient temp air. IOW, much of the action the IAT will see is at the lower part of the table. Let's say I drive the car from spring to fall, so temps may range from 5C to 45 or so.
Having said that, if I had a corresponding MAT installed, while the IAT is seeing a fairly stable temp for air, the MAT temps could continue to rise from heat soak and additonal friction on intake. So I tried to correlate what the current table for MAT has as a compensation and move those values further down the table to the IAT measurements corresponding to the MAT measurements. Let's say the motor is operating nominally at a coolant temp of 80-84C. However, I am driving in 10C weather. Since the ECM is seeing
10C temps, I felt I needed to have the 80C MAT compensation values in the
10C cell of the table at least as a beginning point.
BTW, feel free to tell me I am totally out to lunch on this, but it helps to write it out and check the logic of what I am doing.

01-30-2013	#8
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Re: Fine Tuning: Inj. Offset v BATT Scott, I wrote this on another board dealing w the issue of re-mapping the MAT table when it has been relocated and used as an IAT instead. I appreciate that you keep bringing this topic up because it does interest me particularly since I moved by MAT sensor from the airhorn to a spot behind the air filter but ahead of the airbridge(which BTW needs to be stiffened or it will collapse at WOT). Now the table in the $D0A mask is a MAT Temp C v Compensation. The temps in the table go to 151 C which makes sense since the airhorn is attached to the motor. However, by moving the MAT to an IAT location, my thinking is the IAT will never "see" that 151 C temp since incoming air probably won't go above say 51-55C. And at speed, the IAT should be measuring close to ambient temp air. IOW, much of the action the IAT will see is at the lower part of the table. Let's say I drive the car from spring to fall, so temps may range from 5C to 45 or so. Having said that, if I had a corresponding MAT installed, while the IAT is seeing a fairly stable temp for air, the MAT temps could continue to rise from heat soak and additonal friction on intake. So I tried to correlate what the current table for MAT has as a compensation and move those values further down the table to the IAT measurements corresponding to the MAT measurements. Let's say the motor is operating nominally at a coolant temp of 80-84C. However, I am driving in 10C weather. Since the ECM is seeing 10C temps, I felt I needed to have the 80C MAT compensation values in the 10C cell of the table at least as a beginning point. BTW, feel free to tell me I am totally out to lunch on this, but it helps to write it out and check the logic of what I am doing.